IETF Logo Mail Archive

Re: [rtcweb] FEC for audio?

"Timothy B. Terriberry" <tterriberry@mozilla.com> Mon, 19 May 2014 19:56 UTC

Return-Path: <tterriberry@mozilla.com>
X-Original-To: rtcweb@ietfa.amsl.com
Delivered-To: rtcweb@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5E8B81A03E0 for <rtcweb@ietfa.amsl.com>; Mon, 19 May 2014 12:56:50 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -3.929
X-Spam-Level:
X-Spam-Status: No, score=-3.929 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HELO_MISMATCH_ORG=0.611, HOST_MISMATCH_COM=0.311, RCVD_IN_DNSWL_MED=-2.3, RP_MATCHES_RCVD=-0.651] autolearn=ham
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id E4N_BvEag342 for <rtcweb@ietfa.amsl.com>; Mon, 19 May 2014 12:56:45 -0700 (PDT)
Received: from smtp.mozilla.org (mx1.corp.phx1.mozilla.com [63.245.216.69]) by ietfa.amsl.com (Postfix) with ESMTP id E55EF1A03BC for <rtcweb@ietf.org>; Mon, 19 May 2014 12:55:47 -0700 (PDT)
Received: from [10.252.26.16] (corp.mtv2.mozilla.com [63.245.221.32]) (Authenticated sender: tterriberry@mozilla.com) by mx1.mail.corp.phx1.mozilla.com (Postfix) with ESMTPSA id 4B19EF214D for <rtcweb@ietf.org>; Mon, 19 May 2014 12:55:47 -0700 (PDT)
Message-ID: <537A6190.4060709@mozilla.com>
Date: Mon, 19 May 2014 12:54:56 -0700
From: "Timothy B. Terriberry" <tterriberry@mozilla.com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:19.0) Gecko/20100101 SeaMonkey/2.16.2
MIME-Version: 1.0
To: "rtcweb@ietf.org" <rtcweb@ietf.org>
References: <CAOJ7v-1qEpkWShmw1SQKh4_BLKycF=egu42TS9o9+Smtof36pg@mail.gmail.com> <CAJrXDUESUa-xm9y22OAVKAw5z=WnkY4-X6XFZOoXwvkMoDnaoQ@mail.gmail.com>
In-Reply-To: <CAJrXDUESUa-xm9y22OAVKAw5z=WnkY4-X6XFZOoXwvkMoDnaoQ@mail.gmail.com>
Content-Type: text/plain; charset="ISO-8859-1"; format="flowed"
Content-Transfer-Encoding: 7bit
Archived-At: http://mailarchive.ietf.org/arch/msg/rtcweb/6nt-GzrITmk50cgxtxhA3MM5H0Q
Subject: Re: [rtcweb] FEC for audio?
X-BeenThere: rtcweb@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <rtcweb.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/rtcweb/>
List-Post: <mailto:rtcweb@ietf.org>
List-Help: <mailto:rtcweb-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 19 May 2014 19:56:50 -0000

Peter Thatcher wrote:
> Is there a good reason not to support FEC for audio, if that's what the
> application wants?

I can't think of one. I think we should support FEC for audio.

> On Mon, May 19, 2014 at 9:44 AM, Justin Uberti <juberti@google.com
> <mailto:juberti@google.com>> wrote:
>     Should we specify generic FEC for audio as well as video? Opus has
>     built-in FEC, but it only works for the SILK portion of the payload,
>     meaning that in high bitrate situations, it won't do much for you. I
>     don't know if it has benefits over generic FEC.

The built-in FEC for the SILK layer was meant to cover the case where 
you wanted FEC with no more than one extra frame of latency, but did not 
want to double your bitrate. The reason we did not add built-in FEC for 
the CELT layer was that at the bitrates where CELT operates, we assumed 
traditional codec-agnostic FEC would be used, and thought it an adequate 
solution compared to the extra complexity a codec-specific solution 
would have required.

v2.23.0 | Report a Bug | By Email